-- functions.lua (Corrected for Deadlock issue during interest calculation)

local world_path = minetest.get_worldpath()
local file_path = world_path .. "/accounts"

function normalize_and_tonumber(str)
    if not str then return nil end
    str = str:gsub(",", ".")
    return tonumber(str)
end

local function read_accounts_file()
    local f = io.open(file_path, "r")
    if not f then return { balance = {}, pin = {}, credit = {}, history = {} } end
    local data = f:read("*a")
    f:close()
    if data == "" or data == nil then return { balance = {}, pin = {}, credit = {}, history = {} } end
    return minetest.deserialize(data) or { balance = {}, pin = {}, credit = {}, history = {} }
end

-- CORRECTED: The save function now accepts an optional parameter to bypass the lock.
local function save_accounts_file(data, bypass_lock)
    -- If the interest script is running AND the lock bypass is NOT active, block the save.
    if not bypass_lock and bank_accounts and bank_accounts.is_calculating_interest then
        minetest.log("warning", "[bank_accounts] Save operation blocked: Daily interest calculation is in progress.")
        return false -- Signal failure
    end
    
    local f, err = io.open(file_path, "w")
    if not f then
        minetest.log("error", "[bank_accounts] Could not open accounts file for writing: " .. tostring(err))
        return false
    end
    f:write(minetest.serialize(data))
    f:close()
    return true
end

local function log_transaction(data, player_name, account_type, amount, new_total, trans_type, purpose, other_party)
    if not data.history then data.history = {} end
    if not data.history[player_name] then data.history[player_name] = {} end
    local transaction = { timestamp = os.time(), type = trans_type or "unknown", account = account_type, amount = amount, new_total = new_total, purpose = purpose or "", other = other_party or "" }
    table.insert(data.history[player_name], 1, transaction)
    while #data.history[player_name] > 200 do
        table.remove(data.history[player_name])
    end
end

-- On first run, bypass lock to create file safely.
do
    local f = io.open(file_path, "r")
    if not f then
        save_accounts_file({ balance = {}, pin = {}, credit = {}, history = {} }, true)
    else
        f:close()
    end
end

--- API ---

function bank_accounts.get_account_data(player_name)
    if not player_name then
        return read_accounts_file()
    end
    local data = read_accounts_file()
    if not data.history then data.history = {} end
    return {
        balance = data.balance[player_name] or 0,
        pin = data.pin[player_name] or "0000",
        credit = data.credit[player_name] or 0,
        history = data.history[player_name] or {},
    }
end

function bank_accounts.get_all_data()
    return read_accounts_file()
end

-- CORRECTED: save_all now calls the internal save function with the bypass parameter.
function bank_accounts.save_all(data)
    return save_accounts_file(data, true)
end

function bank_accounts.get_balance(player_name) local data = read_accounts_file(); return data.balance[player_name] or 0 end
function bank_accounts.get_credit(player_name) local data = read_accounts_file(); return data.credit[player_name] or 0 end
function bank_accounts.get_pin(player_name) local data = read_accounts_file(); return data.pin[player_name] or "0000" end

function bank_accounts.add_balance(player_name, amount, trans_type, purpose, other_party)
    local data = read_accounts_file()
    local current_balance = data.balance[player_name] or 0
    local new_balance = current_balance + tonumber(amount)
    data.balance[player_name] = new_balance
    log_transaction(data, player_name, "balance", amount, new_balance, trans_type, purpose, other_party)
    return save_accounts_file(data)
end

function bank_accounts.set_balance(player_name, amount, trans_type, purpose, other_party)
    local data = read_accounts_file()
    local current_balance = data.balance[player_name] or 0
    local new_balance = tonumber(amount)
    local diff = new_balance - current_balance
    data.balance[player_name] = new_balance
    log_transaction(data, player_name, "balance", diff, new_balance, trans_type or "admin_set", purpose, other_party)
    return save_accounts_file(data)
end

function bank_accounts.add_credit(player_name, amount, trans_type, purpose, other_party)
    local data = read_accounts_file()
    local current_credit = data.credit[player_name] or 0
    local new_credit = current_credit + tonumber(amount)
    data.credit[player_name] = new_credit
    log_transaction(data, player_name, "credit", amount, new_credit, trans_type, purpose, other_party)
    return save_accounts_file(data)
end

function bank_accounts.set_credit(player_name, amount, trans_type, purpose, other_party)
    local data = read_accounts_file()
    local current_credit = data.credit[player_name] or 0
    local new_credit = tonumber(amount)
    local diff = new_credit - current_credit
    data.credit[player_name] = new_credit
    log_transaction(data, player_name, "credit", diff, new_credit, trans_type or "admin_set_credit", purpose, other_party)
    return save_accounts_file(data)
end

function bank_accounts.set_pin(player_name, pin)
    local data = read_accounts_file()
    data.pin[player_name] = tostring(pin)
    return save_accounts_file(data)
end

function bank_accounts.player_has_account(player_name)
    local data = read_accounts_file()
    return data.balance[player_name] ~= nil
end

function bank_accounts.create_account(player_name)
    if bank_accounts.player_has_account(player_name) then return false end
    local data = read_accounts_file()
    data.balance[player_name] = 0
    data.pin[player_name] = "0000"
    data.credit[player_name] = 0
    if not data.history then data.history = {} end
    data.history[player_name] = {}
    log_transaction(data, player_name, "system", 0, 0, "Account Created", "Initial account setup")
    return save_accounts_file(data)
end